The present invention relates to an auto-regenerable capacitor and a method of manufacturing the capacitor.
There are already known auto-regenerable capacitors comprising a roll of tapes of dielectric material covered with metallic layers which are extremely thin and constitute electrodes. The automatic regeneration of such a capacitor, subsequent to a momentary, short short-circuit between opposite electrodes, is due to the evaporation of the metal of the electrodes at the point of fault or failure. The end of life of such a capacitor is marked by a short-circuit which renders the electrodes non-reparable. If the short-short circuit current is large it is able to fuse a fusible wire arranged in its circuit. In certain cases, a short-circuit can cause the explosion of the capacitor. The short-circuit current may also be low or lacking in strength at the point at which a fusible wire will not be fused. In this latter case, intense heating takes place in the vicinity of the piercing point and brings about the destruction of the capacitor.
An attempt has already been made to achieve protection against the ill-fated consequences of these defects, by enclosing the capacitor roll in a hermetic casing, deformable under the effect of an internal pressure. Since the destruction of a capacitor roll is generally accompanied by a release of gas, this phenomenon has already been utilized for bringing about the deformation of a portion of the casing to which is secured one end of a rupture wire permitting the capacitor to be removed from the circuit in the event of an increase of the internal pressure.
The mounting of such a rupture wire within the casing is a difficult process which considerably increases the overall cost of the capacitor.